Question: $-\dfrac{6}{2} - \dfrac{9}{10} = {?}$
Explanation: $ = - {\dfrac{6 \times 5}{2 \times 5}} - {\dfrac{9 \times 1}{10 \times 1}} $ $ = - {\dfrac{30}{10}} - {\dfrac{9}{10}} $ $ = - \dfrac{{30} - {9}}{10} $ $ = -\dfrac{39}{10}$